l84 ]M. Desliayes' Monograph of Dentaliiim. 



11. D. BouEi, Desh. D. testd tereti, subarcuatd, longiiudinaliter tenu- 

 issime striata, striis transversalibus decussatd. 



T>. decussatum ? Sowerhy, Min. Conch, pi. 70, f. 5. 

 D. interruptum? Linn,, Gmel. ed., p. 3739, n. 19. 

 Foss. prope Viennam. 



Large, slightly curved, narrow, subulated, attenuated at the posterior 

 extremity ; covered with fine, slightly prominent, closely set, striae, which 

 are more elevated at the posterior extremity than towards the opening, 

 near which they sometimes disappear. These strise are transversely in- 

 tersected by others equally fine, and more closely set, forming a very mi- 

 nute net-work. Other coarser transverse striae indicate the growth. 



Length from 3 inches 2 lines, to 3^ inches. Diameter of the base 

 from 3 to 4 lines. 



12. D. NOVEM-COSTATUM, Lam. D. testd subarcuatd, rosed albiddve, 

 novem-costatd, basi sublmvigatd. 



D. fasciatum. Lam., Ajiim. sans. vert. v. p. 344, n. 7. 



Var. a. Eadem a^bida decern cosfata. 



Habitat prope Rupellam, et in Mari Mediterraneo. — Foss. in Turonia. 



Size middling, slightly curved, with nine slightly prominent ribs, ex- 

 tending from the apex for about two-thirds of its length, diminishing in- 

 sensibly, and disappearing towards the opening. When in fine condition, 

 its colour is rose, with transverse deeper zones, which generally accom- 

 pany the striae indicative of growth ; at other times it is of a uniform 

 greyish-white colour, and occasionally rose-coloured at the apex, and 

 white at the base. Apex usually truncate, with frequently a small tubu- 

 lar prolongation. 



Length 1 inch 6 lines. Diameter of the base scarcely 2 lines. 



13. D. Lessoni, Desh. D. testd subrectd, tereti, albido-grised, acta 

 ad decern costatd, costis obtusis, depressis, ad aperturam evanescen- 

 tibus. 



Habitat in mari Papuensi. 



Allied to D. novem-costatum, but distinguished by its form, curve, and 

 the disposition of its ribs. It is narrow, longer, less curved, constantly 

 of a uniform yellowish white, without transverse zones. Ribs eight, 

 nine, or ten in number, meeting at the base, moderately raised and 



